ACOUSTIC ENHANCEMENT OF HEAT-TRANSFER BETWEEN 2 PARALLEL PLATES

The paper considers a problem in which a steady-state sonic wave is pr opagated in the Longitudinal direction in a fluid enclosed between two horizontal parallel plates which are kept at different temperatures. The distance between the plates is much smaller than the sound wavelen gth. Rayleigh's vortical acoustic streaming that appears in the region between the plates as a result of the sound wave leads to forced heat convection. The effect of that forced convection on heat transferred between the plates is analyzed theoretically. An acoustic Peclet numbe r, which represents the interaction between heat conduction and forced convection is introduced, and asymptotic relations expressing the mea n Nusselt number in terms of this dimensionless group are derived. The results obtained demonstrate that acoustic streaming results in a mar ked enhancement of heat transfer between the plates.